Electric clock



May 8, 1934- s. M. KENERsoN 1,957,543

ELECTRIC CLOCK Filed Dec. 12, 1931 f9.1.v v Ru Sx L C JV Inventar;

I Sarzlfy M gzzem n `v Atty Patented May 8, 1934 UNITED STATES ELECTRIC CLoCK Stanley M. Kenerson, Springfield, Mass., assignor to The Standard Electric Time Company, Springfield, Mass., a corporation of Connecticut Application December 12, 1931, Serial No. 580,625 9 Claims. (Cx. 58-34) This invention relates to the art of resetting clocks at periodic intervals such as once per hour or once per day, the invention being particularly applicable to secondary clocks which are electrically driven by impulses transmitted from a central station at regular intervals such as once per minute.

Objects of the invention are to provide resetting means which are simple and inexpensive to manulO facture, which are reliable and durable in operation, which require no rapid impulses to bring slow secondaries up to correct time, which may Ibe used with any number of wires from the secondary clocks to the central station, which-do not require the transmission of impulses of excessive magnitude from the central station and which are generally superior to those heretofore employed.

In one aspect this invention is characterized in that the energy employed to reset each clock is derived from the regular driving source so that the setting impulse transmitted from the central station need be suiiicient merely to trip the resetting means or otherwise release the resetting force within the clock itself. For example, in systems where each secondary clock is driven by impulses transmitted once per minute, a part of the energy of these driving impulses may be stored for resetting purposes, this potential energy being released at predetermined intervals, e. g. once per hour, to reset the clock. Thus the means which moves the clock train to reset position is actuated solely by the clock litself independently of the resetting impulse, the latter serving merely to release the clock train from its driving means. -Flor the purpose of illustrating the genus of the invention, a typical concrete embodiment is illustrated in the accompanying drawing in which Fig. 1 is a. circuit diagram; Fig. 2 is a. side elevation of the secondary clock with the driving magnet energized;

Fig. 3 is a similar view with the resetting magnet energized;

Fig. 4 is a section on line 4?-4 of Fig. 2; and Fig. 5 is a. top plan of the clock mechanism with themagnets omitted.

The particular embodiment chosen. for the purpose of illustration comprises secondary g clocks having -driving magnets` D forinormally advancing the clock trains in response to impulses received from a central station and resetting magnets R for periodically resetting the secondary clocks. The central station apparatus comprises 4the ratchet wheel 2.

rent B over circuit N to the driving magnets and thence back to the source over the common return C, and a circuit closer H for transmitting resetting impulses to the resetting magnets R over the circuit S and common return C. The circuit closers M and H may be driven by any suitable mechanism' such as a master clock, thev circuit closer M transmitting an impulse say once per minute andthe circuit closer H transmitting an impulse between the same two impulses of each hourly cycle of minute impulses, for example, between the 59th and 60th minute impulses.

As illustrated in Figs. 2 to 5 inclusive each secondary clock comprises two ratchet wheels 1 and 2 having their teeth facing in opposite circumferential directions, the ratchet wheel 1 serving to drive the clock train and the ratchet Wheel 2 serving to prevent overthrow. `The ratchet wheel 1 is driven by magnet D through armature 3, lever 4 pivoted at 5 and pawl 6 pivoted to the lever 4 at 7, the lever 4 carrying a pin 8*- which engages the teeth of ratchet wheel 2. to prevent overthrow. The magnet D also controls,

through an. armature lever 9 pivoted at l0, a de- I tent 11 which engages the ratchet wheel 2 to hold the clock train against forward movement while the pawl 6 is being retracted by the armature 3. The forward or clock-advancing movement of the pawl 6 is eiected either by gravity or preferably by a spring in the usual way. A pawl 12 pivoted at 13 prevents retrograde movement of the clock train while the pawl 6 is retracted.

The resetting magnet R controls a lever 14 pivoted at 15, the lever 14 carrying two pins 16 and 17 which extend under the pawls 6 and l2 respectively. When the magnet R is energized the pins 16 and 17 lift the pawls 6 and 12 out of engagement with the ratchet wheel 1 and, through the medium of lever 4, the pin 16 also lifts the pin 8'out of engagement with With these three parts disengaged from the ratchet wheels, and with the magnet D deenergized to permit the detent 11 to fall away from the ratchet wheel 2, the clock train is free to rotate in either direction. The preferred method of causing the clock train to move automatically to hour position.

when so released consists in'providing a Weight 18 mounted on the minute-hand shaft 20 through an arm 19 so that the gravitational movement of the weight 18 to the lowermost position (Fig. 3) moves the minute-hand to upright position. In order to stop the weight 18 quickly and accurately in its lowermost position, notwithstanding the inherent friction between the rotating parts and their bearings, the magnet 18 is provided with pole pieces 21 and 22 on opposite sides of the lowermost position of the weight 18 and the weight is formed of paramagnetic material so that the pole pieces not only serve as amagnetic brake for the swinging weight but they bring it to rest in its lowermost position. For this purpose the magnet R should of course be energized throughout an interval of time long enough for the weight 18 to come to rest in its lowermost position.

From the foregoing it will be evident that the weight 18 will swing in a clockwise direction if the clock be slow and in a counterclockwise direction if the clock be fast. It will also be evident that instead of using a three-wire system as shown in Fig. 1 the invention is equally applicable to either a one-wire, two-wire or fourwire system. In the case of a four-wire system the magnets D and R could be energized over entirely separate and distinct circuits vinstead of using a common return. In the case of a one-wire or two-wire system the magnets could Cil be connected in parallel across the same circuit with means to cause each magnet to respond only to its own impulses, the one-wire system diiering from a two-wire system only by using a ground return. Means for causing each magnet to respond only to its own impulses are disclosed in copending applications Serial No. 341,176, No. 341,177 and No. 490,200, all assigned to the assignee of this application, and further description is unnecessary for the purpose of the present disclosure.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modications and equivalents which fall within the scope of the appended claims.

I claim:

l. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting the indicator if the clock be slow or fast, the resetting means including a remote-controlled device for releasing the indicator from said driving means and means independent of said device for automatically moving the indicator to a predetermined position when released from the driving means, and magnetic means for quickly stopping the indicator in said position.

2. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting the indicator if the clock be slow or fast, the resetting means including a remote-controlled device for releasing the indicator from said driving means and a weight kinematicaily connected to the indicator for automatically moving it to a predetermined position when the indicator is released from the driving means, and means for quickly stopping the indicator in said position.

3. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting the indicator if the clock be slow or fast, the resetting means including a remote-controlled device for releasing the indicator from said driving means and means deriving energy solely from said driving means for automatically moving the indicator to a predetermined position when released from the driving means, and a magnetic brake for quickly stopping the indicator in said position.

4. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting the indicator if the clock be slow or fast, the resetting means including a remote-controlled device for releasing the indicator from said driving means and means independent of said device for automatically moving the indicator to a predetermined position when released from the driving means, and remote-controlled means for quickly stopping the indicator in said position.

5. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting the indicator if the clock be slow or fast, the resetting means including a remote-controlled device for releasing the indicator from said driving means and a weight always moving in the same sense as the indicator for automatically moving it to a predetermined position when the indicator is released from the driving means, and remote-controlled means for quickly stopping the indicator in said position.

6. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting the indicator if the clock be slow or fast, the resetting means including a remote-controlled device for releasing the indicator from said driving means and means deriving energy solely from said driving means for automatically moving the indicator to a predetermined position when released from the driving means, and a remote-controlled magnetic brake for quickly stopping theindicator in said position.

7. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting. the indicator if the clock be slow or fast, the resetting means including a weight rotatedby said driving means for automatically moving the indicator to a predetermined position when released from the driving means, and remote-controlled means for releasing the indicator from said driving means and quickly stopping the indicator in said position.

8. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting the indicator if the clock be slow or fast, the resetting means including an electromagnet for releasing the indicator from the driving means and magnetically stopping the indicator in a predetermined position and means deriving energy from said driving means for automatically moving the indicator to said position when released from the driving means.

9. A clock comprising a time indicator, means for normally driving the indicator, and means for periodically resetting the indicator if the clock be slow or fast, the resetting means including a weight lifted by energy received from said driving means for automatically moving the indicator to a predetermined position when released from the driving means and an electromagnet for releasing the indicator from the driving means and magnetically stopping the indicator in said position.

STANLEY M. KENERSON. 

